Water heater



S. RADI WATER HEATER April 14, 1953 2 SHEETS-SHEET 1 Filed Dec. 21 1950 INVENTOR.

April 14, 1953 2 SHEETS-SHEET 2 Filed Dec. 21 1950 INVENTOR.

Patented Apr. 14, 1953 UNITED STATES PATENT OFFICE 2,635,173 WATER HEATER Serafino Radi, Milan, Italy Application December 21, 1950, Serial No. 201,919 In Italy December 30, 1949 17 Claims. 1

The present invention relates to an apparatus by means of which the heating of av liquid under pressure maybe attained and, more particularly, this invention relates to an improved heater by means of which water supplied by civic or public supply services may be heated.

Water heater according to this invention are. suitable for domestic use as source of hot water for bath-rooms, and the like, and for industrial use, where a supply of hot water is needed.

The primary object of the present invention is to provide a simple and reliable apparatus which is not subject to the common objection to which water heaters of the conventional type are subject, namely to the danger of explosion or other very serious accidents if some fault or damage in the control or safety devices occurs. According to the current knowledge, water heaters of the conventional type comprise substantially a tank in which water flows under pressure, and one or more heating units directly sunk into said water, a set of safety devices being necessaril provided to prevent overpressure if the temperature rises to the boiling point of water. Moreover, water heaters of conventional type must be constructed so as to safely sustain heavy pressure tests, during which tests the device is worked under high pressures which are well above regular working conditions. This considerably increases the cost of apparatus.

The primary object is attained, according to this invention, substantially by providing a water heater comprising two separate tanks, in one of which Water under pressure may flow, and in the other one of which water or other mum is kept at constant level and in constant communication with the outside. The two tanks are divided by a wall, or partition through which heat may be easily transmitted. In the second tank one or more heating units are sunk, and safety and control devices may be but are not necessarily provided. i

As result, the water under pressure may be heated only by the liquid contained in said second tank, and no dangerous overheating can be caused because said liquid cannot attain a temperature above boiling because said liquid is heated in an open chamber. 4

In a preferred embodiment of this invention,

one tank is arranged inside the other tank, the

inner tank being made of steel, or iron, or copper, or other suitable metal through which heat may easily be transmitted.

The tank in which the heating units areplaced may be supplied with water or another liquid,

according to the use and the requirements. In a preferred embodiment of this invention, the tank is supplied 'with water drawn from the first tank through a passage provided between the two tanks, a suitable constant levelling device being provided for closing said passage as the water in the second tank reaches the, desired level.

Another object of this invention is a general improvement of the constru ti 5 as to allow easy assembly and easy dissembling of the parts comprising the apparatus.

Another object. of this invention is the arrangement of the various operative parts of apparatus so as to allow the supply of heated, pure, soft water to enter the tank in which the water is submitted to direct. action of the heating unit or Lmits.

These objects are attained substantially by onstructing an apparatus comprising an outer larger tank the bottom of which is provided with an opening so dimensioned as to allow introduction of an inner smaller metallic tank, said tank being borne by a plate which becomes a water tight cover for said opening. Through said plate the various heating units, pipes, control and safety devices may be brought inside the interior of said inner-tank, in which the water is kept at constant level and directly heated by the heating units, while the space between the outer surface of the inner tank and the inner surface of the outer tank forms the chamber in which water under pressure flows and is heated. The removal of the plate removes all the several operative units for easy control, maintenance and repair.

With the above objects in view, the present invention will now be described in further detail with particular reference to the accompanying drawings, wherein:

Fig. 1 is a vertical sectional view diagrammatically representing a simplified embodiment of this invention, the apparatus shown comprising the least number of operative parts needed.

Fig. 2 is a vertical sectional View of a preferred embodiment of the present invention.

In the drawing, the various heating units, control and safety devices are, not shown in detail since any device commonly known in the art may be utilized, the present invention not being limited toany particular device of the type mentioned.

Referring first to Fig. 1: a water heater according to this invention comprises an outer tank I provided with an outer insulating covering [9 and with an inlet passage 1 and an outlet passage 9, the latterbeing normally closed by avalve,

(not shown), of any suitable type. Through the inlet passage 3, water or other liquid, which constitutes the heating liquid, may be introduced within the outer tank I, wherein it is kept at constant level 5 by a valve 6 provided with a float 8. At least one heating unit 2 is provided within the tank I and is so arranged as to be fully covered by the heating liquid which is kept at constant level 5. Through the outlet passage 9 the heating liquid can be drawn from tank i when the tank is required for repair, maintenance or cleaning purposes.

The interior of the tank 5 communicates with the exterior through a pipe 3, the inner end A of which is placed near the top of the tank 22 and above the constant level 5 of the heating liquid. Through pipe 3 steam may be freely discharged from the exterior when ebullition of the heating liquid occurs, for example because of operative failure of the automatic control devices or when the heating power of the heating unit is not properly balanced by the absorption of heat. The heating liquid may be discharged too through pipe 3 when its level rises above the regular working level 5, for example because of distortion of the valve 6.

Within tank I, a smaller tank I2 is placed, said tank l2 being made of metal or other suitable material through which heat may be easily transmitted from the heating liquid in tank i to the Water contained in the interior I l of said smaller tank [2, which water constitutes the heated water. The circulation of water under pressure inside tank I2 is achievedthrough an inlet passage [3 and an outlet passage 14. According to the current practice in water heater manufacturing, the inlet passage ends near the bottom of interior space i and the outlet passage i l opens near the top of said space II.

It will be easily understood that since the heated water supplied under pressure into the inner tank I2 cannot be heated to a dangerous temperature because said water is heated by the heating liquid contained in outer tank I, said liquid in turn being unable to reach a temperature above its boiling point at atmospheric pressure, because it is contained in a chamber which is in communication with the atmosphere. At the Very worst, assuming all regular control devices stuck and the valve 6 kept in closed position by distortion thereof, the heating liquid will slowly be exhausted by ebullition. However, this very exceptional occurrence does not cause an accident, because the heat emanated by the heating unit cannot reach the inner tank l2, because of a lack of transmitting medium.

In the preferred embodiment of this invention, an apparatus substantially comprising, in combination, all of above described operative parts, may be usefully constructed in the improved form shown in Fig. 2.

The apparatus comprises an outer tank 2|, externally coated by an insulating wall 22. The tank 2| is shaped in form of an overturned pot, the opening of which is closed by a plate 23 tightly connected to the edge of tank 2| by means of bolts or other suitable means. An annular gasket 24 pressed between the outer portion of plate 23 and the outturned flange 25 of tank 2! ensures a water-tight joint. About the centre of said plate 23 a large opening is provided, through which opening a smaller metallic tank 26 may be introduced into said tank 2|, said tank 26 being in turn carried by a plate 2! firmly secured to the above said plate 23 by means of bolts or other 4 equivalent securing means, a second annular gasket 28 being provided to ensure a tight joint between plates 23 and 2?.

The space 29 within the smaller tank 26 constitutes the chamber in which the heating liquid is kept at constant level, and at atmospheric pressure, while the space Bil between the outer surface of the tank 26 and the inner surface of the outer tank 2! constitutes the chamber in which the heated water may be heated and circu late under pressure. The circulation is actuated through an inlet conduct 3! terminating within space 36 near the bottom of same. The mouth 32 of conduct 3! may be provided with a suitable diiiuser for breaking up the surge of the incoming cold water, said diffuser not being particularly described or shown because any suitable construction may be used. The heated water leaves space 38 through an outlet pipe 33 the opening 34 of which is placed near the roof of tank 2|, according to current practice.

In the preferred embodiment of this invention illustrated in Fig. 2, the heating liquid is constituted by water drawn from space 30, through a passage 35 provided in the roof of the inner tank 26. During regular operation of the apparatus, the passage 35 is kept closed by a valve 38 actuated by a float 31, borne by the same water contained in chamber 29, when the desired level of the water is reached. The upper portion 38 of chamber 29 is in constant communication with the atmosphere through a pipe 39 the opening it of which is placed well above the level at which the water in tank 26 is kept by the constant level device formed by valve 35 and float 31. Any other suitable constant level device may be used in lieu of the one described.

The placing of passage 35 in the upper portion of chamber 36 achieves the remarkable advantage that the water drawn from the chamber 30 is supplied from the upper stratum of water, in which stratum the water is heated so that no material dissolved in the water, and particularly calcium, is brought into the inner space 29.

The heater units are placed within space 29, said units being of any conventional type and, preferably comprising a resistor 42 enclosed in a casing 6!, arranged in the lower portion of space 29 and carried by plate 21'.

According to current practice, an improved water heater substantially as described and shown may be usefully provided with a suitable automatic control device, namely with a thermostat of any conventional type, enclosed in a casing 45 sunk into the heating water contained in chamber 29. The thermostatic device is also borne by plate 21.

Useless consumption of current and damage may be avoided, in the event that by accident the apparatus is started when no water is in chamber 29, by providing an apparatus according to the present invention with a safety device, namely with a fuse 55 made of any known metallic alloy which melts when heated up to a temperature slightly above the boiling temperature of water at atmospheric pressure. The fuse is made part of the feeding circuit of resistor 42 or is electrically connected to said feeding circuit by means of a relay. A suitable casing 43 is provided for protection of fuse 44, said casing being sunk into the heating liquid contained in chamber 29 and borne by plate 21. The casing 45 of the thermostat and the casing 43 of the fuse are shown in the drawing well apart from the casing 4| of heating unit for purposes of clear reason.

In the practical construction of the apparatus, it is useful to arrange the casings near each other, so that radiant heat from the heating unit may quickly warm up both the control device and the safety device, even if no water is contained in chamber 29. Of course, the temperature at which the thermostatic device acts is well below the temperature at which the fuse d4 melts, so that said fuse remains intact except when the thermostatic device is damaged or is inoperative. The fuse is therefore very seldom in operation.

The arrangement of the self-acting control device and of the safety device in the chamber in which heating water is contained results in remarkable advantages, because these devices arranged as mentioned above are sensitive to the temperature Of the liquid in the apparatus which attains the higher temperature. It will be easily understood that the heated water cannot be raised to a higher temperature than that of the heating water because the heat is transmitted to the heated water by means of the heating water according to the present invention.

The described arrangement of the heating unit, of the self-acting control device and of the safety device on the plate 21, the lower surface of which is external, gives other remarkable advantages too, because any one of these units and devices may be easily removed for control, maintenance and repair purposes, when needed. Other advantages are obtained by the fact that said plate 2? is the bearing member of the inner tank 26, in the upper part of which the constant level device is arranged, because the removal of said plate 2'? from plate 23 causes the removal of all operative parts and leaves a large opening in the wall of outer tank 2!, by which access may be had for cleaning, control and maintenance purposes, which is often necessary when the apparatus is supplied with hard or impure water.

It will be understood that the arrangements and the combinations of parts and elements of the assembly described above or parts thereof may find useful application in making devices and apparatus of types other than those described.

While I have illustrated the invention as embodied in a heater for the heating of under pressure water, I do not intend to be limited to the detail shown, since various modifications, improvements and structural change may be made without departing from the spirit and the scope of my invention.

Without further analysis the foregoing will so fully reveal the gist of my invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of the prior art, fairly constitute the essential characteristics of the generic of specific aspects of this invention, and, therefore, such adaptions should and are intended to be comprehended within the meaning and range of equivalents of the following claims.

What I claim as new and desire to have protected by Letters Patent is:

1. An apparatus for heating a liquid under pressure comprising, in combination, a larger tank, a smaller tank placed inside said larger tank, said smaller tank having a wall consisting of a heat-conducting material, means for introducing a liquid into one of said tanks, means for keeping said liquid at a constant level inside said one of said tanks so as to leave the upper 6 part of said one of said tanks free of liquid, means for establishing a permanent communication between the upper part of said one of said tanks and the atmosphere so as to keep the liquid therein at atmospheric pressure, means for heating said liquid kept at constant level and at atmospheric pressure in said one of said tanks, and means for circulating the liquid under pressure in the other of said tanks, said wall being at both sides thereof in heat exchange with said liquids contained in said tanks so as to form a heat-exchanging element between said liquids.

An apparatus for heating a liquid under pressure comprising, in combination, a first largertank, a second smaller tank placed inside said first tank, said second tank being made of a material through which heat may be easily transmitted, means for actuating a circulation of a liquid under pressure into said second smaller tank, means for introducing a liquid into the space confined between said two tanks, means for keeping said liquid at constant level within said space, a communication between the atmosphere and the upper portion of said space, and means for heating the liquid contained at constant level and at atmospheric pressure within said space.

3. An apparatus for heating a liquid under pressure comprising, in combination, a first larger tank, a second smaller tank placed inside said first tank, said second tank being made of a material through which heat may be easily transmitted, means for actuating a circulation of a liquid under pressure into the space confined between said two tanks, means for introducing a liquid into said second smaller tank. means for keeping said liquid at constant level within said second tank, a communication between the atmosphere and the upper portion of said second tank, and means for heating the liquid contained at constant level and at atmospheric pressure in said second tank.

a. A water heater comprising, in combination, a first closed chamber provided with an inlet opening and with an outlet opening, through which openings water under pressure may fill said chamber and circulate therethrough, a second chamber separated from said first chamber by a metallic wall, a communication between said chambers, means being provided for closing said communication as water drawn from said first chamber attains a predetermined level within said second chamber, a passage one end of which is open to the atmosphere and the other end of which is open within said second chamber above said predetermined level, and means for heating the water kept at said predetermined level and at atmospheric pressure in said second chamber.

5. A water heater comprising, in combination, a larger tank, a smaller tank placed inside said larger tank, said smaller tank being made of a material through which heat may be easily transmitted, means for actuating a circulation of water under pressure into one of said tanks, a communication between said two tanks through which communication water may be drawn inside the other one of said tanks, a constant level self-acting valve closing said communication as water drawn inside said other tanks attains a predetermined level, a communication between the upper portion of said other tank and the at-.- mosphere, and means for heating the water contained at constant level and at atmospheric pressure inside said other tank. a

accede-s 6. A water heater'comprising, in combination, a first larger tank, a second smaller tank placed inside said first tank, said second tank being made of a material through which heat may be easily transmitted, means for actuating a circulation of water under pressure into the chamber comprised between said two tanks, a communication between said chamber and the interior of said second smaller tank through which communication water may be drawn from said chamber into said second tank, a constant level self-acting valve closing said communication as said drawn water attains a predetermined level within said second tank, a communication between the atmosphere and the portion above said level in the interior of said second tank, and means for heating the water-kept at constant level and at atmospheric pressure within said second tank.

'7. In a water heater as claimed in claim 8, a constant level valve comprising a valve abutting on a seat provided in the passage through which the first tank communicates with the second tank, and a fioat corne by the levelled liquid inside the second tank and acting on said valve.

8. In a Water heater as claimed in claim 6, an insulating coating covering the outer larger tank.

9. In a water heater comprising two chambers, in one of which water circulating under pressure is heated by transmission through the wall dividing said chambers by water contained at constant level and at atmospheric pressure in the other of said chambers and subject to direct action of heating units, the provision of a passage between said two chambers, so that between said passage water may be drawn from the first of said chambers into the other one, and the provision of a constant level valve for closing said passage as the drawn water attains said level in said other chamber.

10. In a water heater comprising two chambers in one of which water circulating under pressure is heated by transmission through the wall dividing said chambers by water contained at constant level and at atmospheric pressure in the other one of said chambers and subject to direct action of heating units, the provision or" a passage between said chambers and provided with a constant level valve for closing said passage as the water drawn from said first chamber to said second chamber attains a predetermined level inside said second chamber, and the arrangement of said passage in the upper portion of said chambers,

11. In a water heater comprising a larger tank and a smaller tank placed inside said larger tank, heating units placed inside said smaller tank for heating water kept at constant level and at atmospheric pressure inside said smaller tank, and means for actuating a circulation of water under pressure in the space confined between said two tanks, in which space said water is heated through the wall of said smaller tank by the water contained in the latter and subject to direct action of said heating units, the provision of a passage through said wall, said passage being provided with a constant level valve for closing said passage as Water drawn through said passage into said small-er tank attains a predetermined level, and the arrangement of said passage near the top of said inner tank.

12. A water heater comprising, in combination, an outer tank provided with an insulating coating, an inner metallic tank enclosed in said outer tank and dividing the interior or" the latter in two chambers, the chamber comprising between the outer surface of the inner tank and the inner surface 01 the outer tank being provided with an inlet passage and with an outlet passage through which passages a circulation of water under pressure may be actuated into said chamber, a passage provided through the wall of said inner tank and positioned near the top of same, a valve inside said passage for closing the same, a float connected to said valve and placed inside said inner tank, said float being arranged for operating said valve in closed position as the water inside said inner tank reaches a level, a heating unit placed inside said inner tank below said level, an open pipe crossing the wall of the inner tank, one end of said pipe being placed in the interior of said inner tank above said level and the other end being externally placed about the apparatus.

13. A water heater comprising, in combination, an outer tank provided with an insulating coating, an inner metallic tank enclosed in said outer tank and dividing the interior of the latter in two chambers, the chamber comprised between the outer surface of said inner tank and the inner surface of said outer tank being provided with an inlet passage and with an outlet passage through which passages a circulation of water under pressure may be actuated into said chamber, a passage provided through the wall of said inner tank and positioned near the top of the same, a valve inside said passage for closing the same, a fioat connect-ed to said valve and placed inside said inner chamber, said float being arranged for operating said valve in closing position as the water inside said inner tank reaches a predetermined level, a communication between the upper portion of the chamber comprised inside said inner tank and the atmosphere, an electric heating unit placed inside said inner tank and below said level, a thermostatic device placed inside said inner tank and below said level, said thermostatic device being electrically connected to the feeding circuit of said heating unit, and a fuse placed inside said inner tank and near said heating unit, said fuse being part of an electric circuit connected to the said feeding circuit.

14. In a water heater comprising two tanks one of which is placed inside the other and forming two chambers, in one of which water under pressure may circulate and be heated. by heated water contained at constant level and at atmospheric pressure in the second chamber, an outer assembly comprising the outer tank, the bottom of which is provided with an opening so dimensioned that the inner tank may be introduced therethrough, and an inner assembly comprising the inner tank the bottom of which is connected to a plate, said plate being removably connected to the bottom of said outer tank and forming a closure for the opening of the latter.

15. In a water heater comprising an outer tank and an inner tank, means for actuating a circulation of water under pressure inside the chamber comprised between said two tanks, means for keeping a liquid at constant level and at atmospheric pressure inside the interior of said inner tank, heating units and heating control devices placed inside said inner tank, an outer assembly comprising the outer tank the bottom of which is provided with an opening so dimensioned that the inner tank may be introduced therethrough, and an inner assembly comprising the inner tank, a plate bearing said inner tank and forming an out-turned flange around the bottom of said tank, and securing means for tight connection of said flange to the edge of said opening, said heating units and control devices being introduced through and borne by said plate.

16. A water heater comprising, in combination, an outer tank in shape of an inverted pot and coated with an insulating coating, the bottom of said tank being closed by a plate secured to an out-turned flange provided on the edge of said tank, a round of bolts as securing means between the contour of said plate and said outturned flange, an annular gasket between said contour and said flange, an opening about the centre of said plate, a second plate covering said opening and removably connected to said first plate by means of a second round of bolts, a second annular gasket between said two plates, a metallic tank borne by said second plate and arranged through said opening and into said outer tank, an inlet pipe through said first plate, the end of said pipe being placed near the bottom of the chamber confined by the inner surface of the outer tank and by the outer surface of said inner metallic tank, an outlet pipe through said first plate, the intake opening of said outlet pipe being placed near the top of said chamber, an inner tank placed inside said outer tank and introduced therein through said opening provided in said bottom plate, said inner tank being borne by the said removable second plate, a pipe going through said second plate, one end of said pipe being placed in the chamber enclosed in said inner tank and near the top of same, a communication going through the top of said inner tank, a valve arranged along said communication and operated by a float, said float being placed inside said inner tank and so positioned that the floating of the same on the liquid drawn into said inner tank through said communication, as said liquid attains a predetermined level brings said valve in closed position, a heating unit comprising a resistor and borne by said second plate and placed inside said inner tank, a thermostatic device borne by said second plate and placed inside said inner tank, said thermostatic device being electrically connected to the feeding circuit of the resistor for control of the current supply to said resistor, a fuse borne by said second plate and placed inside said second tank, said fuse being part of a circuit connected to the feeding circuit of the resistor for cutting off the current supply to said resistor as said fuse melts.

17. An apparatus for heating a liquid under pressure, comprising, in combination, a first tank; a second tank located within said first tank, said second tank being in direct heat exchange with said first tank; means for supplying a liquid to one of said tanks; means for keeping said liquid at a constant level within said one of said tanks so as to leave the upper part thereof free of liquid; means for establishing a permanent communication between said upper part of said one of said tanks and the atmosphere so as to keep the liquid therein at atmospheric pressure; means for heating said liquid in said one of said tanks; and means for circulating the liquid under pressure in the other of said tanks, said liquid under pressure being heated by the heat exchange between said tanks.

SERAFINO RADI.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,047,389 Cooper Dec. 17, 1912 1,926,252 Wright et al Sept. 12, 1933 2,115,601 Whitby et a1. Apr. 26, 1938 2,224,131 Bailey Dec. 10, 1940 FOREIGN PATENTS Number Country Date 9396/32 Australia Sept. 27, 1932 241,364 Switzerland July 1, 1946 

